Missing assets

A recent site audit for my site has shown some missing stylesheets for this plugin. I’ve had a look through the code and it looks like it’s trying to enqueue two stylesheets that aren’t in the assets folder of the plugin.

wp_enqueue_style('jquery-ui' , plugins_url('assets/css/jquery-ui.css', __FILE__) );
wp_enqueue_style('datepicker' , plugins_url('assets/css/datepicker.css', __FILE__) );

Both of these lines are trying to include styles that aren’t present. Could you take a look at this please?